Postherpetic neuralgia

Postherpetic neuralgia (post-hur-PET-ik noo-RAL-juh) is a complication of shingles, which is caused by the chickenpox (herpes zoster) virus. Postherpetic neuralgia affects nerve fibers and skin, causing burning pain that lasts long after the rash and blisters of shingles disappear.

The risk of postherpetic neuralgia increases with age, primarily affecting people older than 60. There's no cure, but treatments can ease symptoms. For most people, postherpetic neuralgia improves over time.

The signs and symptoms of postherpetic neuralgia are generally limited to the area of your skin where the shingles outbreak first occurred — most commonly in a band around your trunk, usually on one side of your body. However postherpetic neuralgia is also common in people whose shingles occurred on the face.

Signs and symptoms may include:

Pain that lasts 3 months or longer after the shingles rash has healed. The associated pain has been described as burning, sharp and jabbing, or deep and aching.

Sensitivity to light touch. People with the condition often can't bear even the touch of clothing on the affected skin (allodynia).

Itching and numbness. Less commonly, postherpetic neuralgia can produce an itchy feeling or numbness.

When to see a doctor

See a doctor at the first sign of shingles. Often the pain starts before you notice a rash. Your risk of developing postherpetic neuralgia is lessened if you begin taking antiviral medications within 72 hours of developing the shingles rash.

Once you've had chickenpox, the virus remains in your body for the rest of your life. As you age or if your immune system is suppressed, such as from medications or chemotherapy, the virus can reactivate, causing shingles.

Postherpetic neuralgia occurs if your nerve fibers are damaged during an outbreak of shingles. Damaged fibers can't send messages from your skin to your brain as they normally do. Instead, the messages become confused and exaggerated, causing chronic, often excruciating pain that can last months — or even years.

No single treatment relieves postherpetic neuralgia in all people. In many cases, it takes a combination of treatments to reduce the pain.

Lidocaine skin patches

These are small, bandage-like patches that contain the topical, pain-relieving medication lidocaine. These patches can be cut to fit only the affected area. You apply the patches, available by prescription, directly to painful skin to deliver temporary relief.

Capsaicin skin patch

A high concentration of an extract of chili peppers (capsaicin) is available as a skin patch to relieve pain. Available only in your doctor's office, the patch is applied by trained personnel after using a numbing medication on the affected area. The process takes at least two hours, but a single application is effective in decreasing pain for some people for up to three months. If effective, the application can be repeated every three months.

Anticonvulsants

Certain anti-seizure medications, including gabapentin (Neurontin, Gralise) and pregabalin (Lyrica), can lessen the pain of postherpetic neuralgia. These medications stabilize abnormal electrical activity in your nervous system caused by injured nerves. Side effects of these drugs include drowsiness, unclear thinking, unsteadiness and swelling in the feet.

Antidepressants

Certain antidepressants — such as nortriptyline (Pamelor), duloxetine (Cymbalta) and venlafaxine (Effexor XR) — affect key brain chemicals that play a role in both depression and how your body interprets pain. Doctors often prescribe antidepressants for postherpetic neuralgia in smaller doses than they do for depression alone.

Common side effects of these medications include drowsiness, dry mouth, lightheadedness and weight gain.

Opioid painkillers

Some people may need prescription-strength pain medications containing tramadol (Ultram, Conzip), oxycodone (Percocet, Roxicet, Xartemis XR) or morphine. Opioids can cause mild dizziness, drowsiness, confusion and constipation. They can also be addictive. Although this risk is generally low, discuss it with your doctor.

Tramadol has been linked to psychological reactions, such as emotional disturbances and suicidal thoughts. Opioid medications should not be combined with alcohol or other drugs and may impair your ability to drive.

Steroid injections

Steroids are sometimes injected into the spine (intrathecal) for postherpetic neuralgia. However, evidence of effectiveness is inconsistent. A low risk of serious side effects, including meningitis, has been associated with their use.

You may find that the following over-the-counter medications ease the pain of postherpetic neuralgia:

Capsaicin. Capsaicin cream, made from the seeds of hot chili peppers, may relieve pain from postherpetic neuralgia. Capsaicin (Capzasin-P, Zostrix) can cause a burning sensation and irritate your skin, but these side effects usually disappear over time. Because capsaicin cream can irritate your skin, avoid getting it on unaffected parts of your body. Follow instructions, including wearing gloves for application and washing your hands thoroughly after applying.

The herpes zoster vaccine (Zostavax) has been shown to greatly decrease the risk of shingles. The vaccine is approved by the Food and Drug Administration for adults age 50 and older and is recommended for all adults 60 and older who aren't allergic to the vaccine and who don't take immune-suppressing medications.